Hauv kev lag luam mining, worm gears ua lub luag haujlwm tseem ceeb hauv ntau daim ntawv thov vim lawv muaj peev xwm los tuav cov khoom hnyav, muab lub zog siab, thiab muaj kev ua tau zoo raws li qhov xav tau. Nov yog qee qhov tseem ceeb ntawm kev siv worm iav hauv mining: Daim ntawv thov hauv Min ...
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